Accord drops rpms as it heats up then kills.

My 1990 Honda Accord will start and run OK when cold, then, with steadily
increasing intervals, the RPM's will drop to almost nothing for a few
seconds then speed up and run good again. As it gets hotter, the time that
it runs at low, low RPM get longer until it finally kills. It will not
restart and run until it cools again. Adjustments to the idle have had no
effect. Unplugging the fast keeps it in the low, low rpm, but I cannot get
it to run any higher. I've replace the distributor (with all components
including the CRANK sensor), the fuel inj relay, the MAP sensor, the fuel
filter, plugs, air filter, fuel pump, and fuel pressure regulator. I've
checked for vacuum leaks and didn't find any. The only code the ECU ever
gave me is 43. It wasn't listed in the repair manual, but I found on the
internet that is a general fuel system fault code (meaning it could be
anything). If I unplug the Oxygen sensor and advance the timing way up, I
can keep it running, but as soon as I put a load to the engine (try to
drive) it drops RPM and kills.

Has anyone had a similar problem with their Accord that can give me some
direction on fixing the problem? Thanks.

 

check inside the radiator and make sure the coolant is full to the top.

 

Check temp sensor as well?

 

Just to let everyone know, you help me solve the problem. After
investigating engine temperature related items, I discovered an engine
block mounted coolant temperature sensor, just under the distributor.
After replacing this sensor, which sends data to the ECU, my rpm problem
stopped. I was always checking the sensor you can see easily that sits in
from of the thermostat. I'm told that that one controls the cooling fan
(and probably the temp gage on the dash).

Thanks again for your help.